The invention relates to a device for analyzing fluid samples consisting of a sample chamber containing at least one testing device, which comprises a control and analysis device and a filling and draining device, through which, respectively, a fluid sample taken from a quantity of fluid is fed into the sample chamber and removed from it.
A typical area of application for such testing equipment is in waste water analysis. In this type of application, a fluid sample is taken from the waste water and tested in the sample chamber. Frequently, a reagent is added in the sample chamber and its reaction with the fluid sample is completed and measured. Gas-selective or ion-selective sensors, pH sensors, photo-optical sensors, and other sensors are commonly used for tests performed inside the sample chamber. A gaseous reaction product which develops during the reaction can be fed into a measuring device designed specifically for measuring this product, such as a CO.sub.2 detector (published journal article by M. Levermann, "TOC Testing in an On-line Process", publication "Chemie, Umwelt, Technik" [Chemistry, Environment, Technology], 94, pages 12-15).
To fill the sample chamber, the fluid sample must be conveyed from the available quantity of fluid, such as waste water, through a supply line
An unavoidable feature of such testing, particularly of waste water samples, is that deposits form in the fluid lines used to fill and drain the sample chamber. Unless they are routinely flushed--a relatively expensive procedure--there is a risk that these lines may become clogged.
Consequently, the objective of the invention is to design a device of the type specified initially in such a way that the sample chamber can be easily filled and drained without running the risk of clogging the fluid lines and incurring the substantial expense of rinsing.